The National Fenestration Rating Council board approved Lawrence Berkeley National Lab WINDOW 7.8.71 and THERM 7.8.71 for immediate use for NFRC simulation and certification purposes.
The LBNL-developed software program called WINDOW, which stands for "Thermal-Window Optical and Solar-Optical Analysis" program, is used for the thermal and optical analysis of windows, glazing systems and other fenestration products (components like windows, doors and skylights) to evaluate their energy performance. The THERM software program is used for simulating the heat transfer and thermal performance of building components, particularly fenestration systems such as windows, doors and curtain walls. The name "THERM" stands for "Two-Dimensional Thermal Transfer."
Use of WINDOW 7.8.71 & THERM 7.8.71
Beginning on August 18, WINDOW 7.8.71 / THERM 7.8.71 may be used and it is strongly recommended that use of the new version be implemented by laboratories immediately on any current work since there have been several updates. Beginning Oct. 1, 2023, WINDOW 7.8.71 / THERM 7.8.71 shall be the only approved software for NFRC 700 ratings for new certifications, recertification or revisions/addendums.
Sunset of WINDOW 7.8.57/THERM 7.8.57
WINDOW 7.8.57 / THERM 7.8.57 shall no longer be used after Sept. 30, 2023. The NFRC certification of products modeled in accordance with the Component Modelling Approach for NFRC 705 certification within CMAST shall continue to use WINDOW 6.3 / THERM 6.3. The Component Modelling Approach is the only program not affected by the sunset date.
